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because we have a great waste water system here in san francisco, we do about 80 million gallons of waste water here in san francisco, which means we basically fill up 120 olympic sized swimming pools each and every day here in the city. we protect public health and safety and environment because we are discharging into the bay and into the ocean. this is essentially the first treatment here at our waste water treatment facility. what we do is slow down the water so that things either settle to the bottom or float to the top. you see we have a nice selection of things floating around there, things from bubble gum wrappers, toilet paper, whatever you dump down the toilet, whatever gets into our storm drains, that's what gets into our waste water treatment and we have to clean. >> see these chains here, this keeps scum from building up. >> on this end in the liquid
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end basically we're just trying to produce a good water product that doesn't negatively impact the receiving water so that we have recreation and no bad impact on fish and aquatic life. solids is what's happening. . >> by sludge, what exactly do you mean? is that the actual technical term? . >> it's a technical term and it's used in a lot of different ways, but this is organic sewage sludge. basically what it is is, oh, maybe things that come out of your garbage disposal, things that are fecal in nature. it's sludge left in the water after the primary treatment, then we blend those two over and send them over to digestion.
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this building is built to replace tanks here that were so odoriferous they would curl your hair. we built this as an interim process. >> is there a coagulant introduced somewhere in the middle of this? . >> this coagulant brings solids together and lets the water run through. that gives us more time in the digestion process, more time to reduce the amount of solids. these are the biggest ones in the world, like we always like to do in san francisco. they are 4 meter, there's none like it in the world. >> really? wow. >> three meters, usually. we got the biggest, if not the best. so here we are. look at that baby hum. river of sludge. >> one of the things is we use bacteria that's common in our
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own guts to create this reduction. it's like an extra digestion. one of the things we have to do to facilitate that is heat that sludge up and keep it at the temperature our body likes, 98.6 degrees. >> so what we have here is the heat exchanger for digester no. 6. these clog up with debris and we're coming in to -- next wet weather season so we always come through here, clean them out, make sure that we get maximum heat exchange during the colder wet weather. sludge season. >> rubber glove. >> right here. >> rubber glove, excellent. all right, guys. >> thank you. >> good luck. >> this is the full on hazmat.
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. >> residual liquid. we're taking it time to let it drain. we don't want to get sludge on it necessarily. take your time. stand on the side of it. . >> should we let it release for a while? . >> let it release. >> is that the technical term? . >> this is the most important bolt on the whole thing. this is the locking bolt. it locks this thing right in place. so now. >> take your hammer and what we want to do, we get rag build up right in here. the hot water recirculates right in here, the sludge recirculates in here. the sludge sometimes has rags in it. all we want to do is go around the clean the rags. let me show you how.
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take the slide hammer, go all the way through the back, go around. >> got you. >> during the real rainy season, how does that change the way dealing with this job? is it a lot more stuff in there? . >> what we do, charles, we do this quarterly. every four months we go around and clean all the heat exchangers so we don't have a large build up. . >> go around? . >> yeah. (sound of hammering). >> what i'm trying to do, charles, is always pull it out on the low stroke. >> right.
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so you are not, like, flying out. now talk about clean up. . >> then where does this stuff get deposited? . >> we're going to dump it in a debris box and it will go back to the plant. >> if you think back, the romans came up with a system of plumbing that allowed us it use water to transport waste away from the hub of civilization, which enabled cities to grow. . >> you have a large bowl, a drive motor and another motor with a planetary gearbox with differential pressure inside there. the large mass up there spinning separating the solids from the liquid. we have to prevent about once a
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month, we go in there grease those, change the oil, check the vibration levels. the operators can tell just by the hum of that machine that it's a harmonic noise emitted that it's out of balance and the machine needs to be cleaned. it will start vibrating and we have vibration analysis machines that will come over here and check the levels. so it's kind of an on-going thing that you have to stay on top of on a daily basis. >> handled properly, you take organic residuals, as we call them, that are leftovers of our society and turn them back into some energy. and we have another ability to take that sludge and get a nutrient value for crops there.
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we actually are running a kind of composting energy recovery system. >> well, this is a dirty job. we try to do it safely and we try to do it without imposing too much on the public. people want to flush their toilets and have things go away and not be bothersome again. we do a lot to try to accomplish that. i'd like to invite you to come back any time you want. once you got this in your blood, you are not going to be able to stay away. the raging waters are fun and when we do digester cleaning i really hope you can come back. that's quite a sight. >> yeah, that sounds interesting. >> i really appreciate you coming by and it was a